In apparatuses for sealing a lamp mount to a lamp tube of the prior art, the lamp mount was heretofore sealed to an end of the lamp tube by pushing the lamp mount having a filament coil mounted thereon into the end of the lamp tube, heating a flare of said lamp mount with a burner until it was softened, urging the softened flare of the lamp mount against the end of the lamp tube with a pusher plate into a close contact therewith, and heating the flare and the end of the lamp tube simultaneously and sufficiently until they were softened and fused together into a completely sealed condition.
In this conventional sealing apparatus, however, since the pusher plate was not specifically heated, it suffered from a disadvantage that the urging of the flare of the lamp mount caused a temporary cooling of the flare so that the reheating and softening of the flare was not effected speedily and efficiently.
Further, since the flare and the end of the glass lamp tube were merely mechanically urged together by the pusher plate, it was sometimes difficult to effect a close contact therebetween particularly when the end face of the lamp tube was more or less inclined or when the flare of the lamp mount was somewhat distorted and, accordingly, it was necessary to use special care in reheating them until they fused and it was difficult to perform the sealing step at a high speed.